A recording apparatus, such as an ink jet recording apparatus which forms an image on recording medium by depositing liquid ink on the recording medium with the use of an ink jet recording head, is relatively low in the noise level during a recording operation, can form minute dots on recording medium, and also, can place minute dots on recording medium at a high density. Thus, it has come to be widely used in the field of printing, including the field of color printing. Some ink jet recording apparatuses are provided with: an ink jet recording head, which receives ink from an ink container which is separably attached to the ink jet recording head; a carriage on which the recording head is borne, and which is moved so that the recording head is moved (primary scan) relative to the recording medium in a manner to scan the recording medium in a preset direction; and a conveying means which conveys (secondary scan) the recording medium relative to the recording head in the direction perpendicular to the abovementioned direction in which the carriage is moved. They record an image by jetting ink while moving the recording head in the primary scan direction. Further, some ink jet recording apparatuses can print in full color. In the case of those ink jet recording apparatuses, multiple recording heads capable of jetting black ink, and color inks, such as yellow, cyan, and magenta inks, respectively, are mounted on the carriage so that not only a monochromatic image can be printed (for example, text can be printed using black ink), but also, a full-color image can be printed by varying the ratio at which each ink is jetted.
Presently, the mainstream structural arrangement for supplying the ink jet recording head of an ink jet recording apparatus with ink is such that an ink container having an ink storage portion is independent from a recording means, and also, that both the ink container and recording means are independent (separable) from the main assembly of a recording apparatus, and are attached to the main assembly when they are put to use. In the case of this structural arrangement, the ink passage from the ink storage portion to the recording means is short, and therefore, it is easy to reduce in size a recording apparatus. Also in the case of this structural arrangement, it is only the ink storage portion that needs to be replaced to replenish the recording means with ink. Therefore, this structural arrangement is advantageous in terms of operational cost.
Regarding the structural arrangement for supplying an ink jet recording head with ink, in order for the ink container portion and recording means to be separable from each other, it is desired that the portion of an ink container, by which the ink container is connected to a recording means (this portion of ink container hereafter will be referred to as “connective portion”), simultaneously satisfies at least the following three conditions.
One of the conditions is that the connective portion does not leak ink, regardless of ink container attitude, when the recording means and ink container are in connection with each other (which hereafter will be referred to as “connected state”) and also, when the recording means and ink container are not in connection with each other (which hereafter will be referred to as “disconnected state”). The next condition is that the connective portion ensures that the recording means is reliably supplied with ink while the recording means and ink container are in connection with each other. It is possible that a recording means and an ink container will be repeatedly connected to each other or disconnected from each other by a user. Thus, another condition, or the third condition, is that even if a recording means and an ink container are repeatedly connected to each other, or disconnected from each other, the conditions to be satisfied when the two are in the connected or disconnected state, are satisfied each time the two are connected or disconnected.
A couple of structural arrangements that satisfy the abovementioned conditions are disclosed in Japanese Laid-open Patent Applications H07-241998 (Patent Document 1) and 2000-85138 (Patent Document 2). According to these patent applications, a piece of hollow tube is used as a means for connecting an ink container and a recording means in such a manner that liquid can be moved between the ink container and recording means, that is, a means for connecting the interior of the ink container and the interior of an ink jet recording head. As the structural arrangements which use a needle to connect a head and an ink container to each other, those disclosed in Japanese Laid-open Patent Applications H05-229133 (Patent Document 3), H05-254139 (Patent Document 4), H05-270001 (Patent Document 5) may be listed. In the case of the structural arrangements disclosed in Patent Documents 1-5, the gap between the external surface of a tubular member and the counterpart can be easily sealed with an elastic member, such as an O-ring, and further, a large amount of ink can be supplied at a high speed through the tubular member.
In the case of many of the structural arrangements such as those disclosed in Patent Documents 1-5, a connective portion, such as an ink supplying needle, is vertically pointed for the following reason. That is, the ink in an ink container is likely to collect in the bottom portion of the ink container because of gravity. Further, in the case of an ink container structured so that as the ink in the ink container is consumed, the ambient air is drawn into the ink container, the ink outlet of the ink container must be located in the bottom portion of the ink container, because, unless the ink outlet is in the bottom portion of the ink container, a large amount of the ink in the ink container is unusable, being therefore wasted. Therefore, in the case of an ink container structured as described above, its ink outlet is likely to be located in its bottom portion.
Thus, in the case of the structural arrangement in which an ink container and a recording head are connected to each other with the use of a tubular member, and the ink outlet of the ink container is a part of the bottom portion of the ink container, the ink container is mounted into the recording apparatus, from above, in the direction parallel to the direction in which the tubular member extends.
However, the above described example of the structural arrangement for connecting an ink container to an ink jet recording head suffers from the problems which will be pointed out below.
Firstly, since the ink container is mounted into the recording apparatus from above and in the direction parallel to the direction in which the tubular member extends, a certain amount of space must be provided in the adjacencies of the top surface of the recording apparatus when using the apparatus, and also, the recording apparatus must be more or less limited in design. For the purpose of supplying an ink jet recording head with ink at a speed high enough for the high speed printing in future, the tubular member must be larger in internal diameter. However, mounting an ink container into the recording apparatus from above makes it difficult to accurately position the ink container, and therefore, there is a limit to the size of the diameter of the tubular member.
Secondly, in the case of the structural arrangements disclosed in Patent Documents 1-5, a means for sealing the opening of the ink inlet of the tubular (hollow) member when disconnecting the ink container from the ink jet recording head is not provided. Therefore, it is possible that when the ink container is not in connection with the ink jet recording head, the solvent portion of the ink will evaporate through the opening of the ink inlet, changing thereby the ink in properties, and/or foreign substances will enter the ink container through the opening of the ink inlet. It is possible to provide a sealing means which is slidable along the tubular member to seal the opening of the ink inlet. However, not only does this structural arrangement increase component count, but also, the provision of the sealing means requires the ink container to be positioned higher than an ink container with no sealing means, resulting in the increase in the recording apparatus height. Further, in the case of Patent Document 2, the opening of the needle is sealed with a film-like member. In this case, however, as the ink container is attached to the recording head, the sealing film is broken. Therefore, if the ink container is separated from the ink jet recording head before the ink in the ink container is used up, it is possible that the ink will leak through the needle.
Thirdly, what has been in demand is a compact recording apparatus, in particular, a compact recording apparatus which is small in vertical dimension. Therefore, an ink container has been reduced in the height which the ink container has when it is in use. However, an ink container is not to be easily reduced in ink capacity. Accordingly, therefore, an ink container has to be increased in length. Thus, there occurs a situation in which an oblong ink container has to be mounted into a recording apparatus, while being roughly horizontally held. In such a situation, it is even more difficult to align a tubular connective member with the ink outlet. Therefore, misalignment sometimes occurs between the tubular connective member and the ink outlet. If the ink container is mounted, with the tubular connective member remaining misaligned with the ink outlet, ink is likely to leak, and/or sometimes, the tubular connective member breaks because of the force to which it is subjected when it is connected to the ink outlet.
As the means for properly positioning a tubular connective member relative to the ink outlet, it is possible to provide both a recording head and an ink container with a guide to improve them in terms of the accuracy with which they can be positioned relative to each other. However, in consideration of the fact that each ink container is different from the others in terms of the component dimension, the guides need to be structured so that a minute gap is provided between them. This gap inevitably makes it possible for the tubular connective member and ink outlet to become misaligned by the amount equal to the amount of the gap.
Fourthly, in the case of the structural arrangement disclosed, as the third embodiment, in Patent Document 2, in which an ink delivery needle is provided as a part of an ink container, a protective member, such as a guiding cylinder, must be provided for user protection, and also, for preventing the needle from being damaged. This increases an ink container in size. Further, if a guiding cylinder is provided, it is possible that the guide cylinder itself becomes damaged due to a fall or the like.